A conventional optical time-division multiplexer is described, for example, in Proceedings of the 1994 Spring Conference of the Institute of Electronics, Information and Communication Engineers, pp. 4-443-4-444. An optical time-division multiplexer described in this publication has two optical fibers, including an optical delay generator and an optical coupler. The two optical fibers connect two input ports of the multiplexer with the optical coupler. One of the two optical fibers is longer than the other one so that there is a delay in the arrival at the coupler of a signal in the longer fiber relative to the arrival of a signal in the shorter fiber;
In a conventional optical time division multiplexer, the delay time depends upon the lengths of optical fibers. However, the length of optical fibers expand or contract according to the surrounding temperature. Thus, the delay time also depends on the temperature. Therefore, a variation in the temperature will change the delay time and may thus introduce errors into the operation of a conventional optical time-division multiplexer, or any other device which relies upon the length of optical fibers to create a time delay.